1. Field of the Invention
This invention relates to a manufacturing method of a semiconductor device, specifically to a manufacturing method of a BGA (Ball Grid Array) type semiconductor device which has ball-shaped conductive terminals.
2. Description of the Related Art
A BGA type semiconductor device has been known as a kind of surface-mount type semiconductor device. A plurality of ball-shaped conductive terminals made of a metal material such as solder is arrayed in a grid pattern on one principal surface of a package substrate and is connected with a semiconductor die bonded on the other principal surface of the substrate in the BGA type semiconductor device. When the BGA type semiconductor device is mounted into electronic equipment, the semiconductor die and external circuit on a printed circuit board are electrically connected by thermally bonding each of the conductive terminals to each of wiring patterns on the printed circuit board.
Such a BGA type semiconductor device is known to have advantages in providing a large number of connection terminals as well as reducing the size over other surface-mount type semiconductor devices such as an SOP (Small Outline Package) and a QFP (Quad Flat Package), which have lead pins protruding from their sides.
The BGA type semiconductor device was adopted into a CCD image sensor in recent years, and has been used as an image sensor chip mounted in a mobile telephone which is strongly required to reduce the size.
On the other hand, three-dimensional packaging technologies have come to attention, which use a wafer level CSP (Chip Size Package) or a technology to make through-hole interconnection in silicon substrate. These technologies include a method to make through-hole interconnection in silicon substrate after bonding multi layers of chips and a method to stack silicon wafers after making through-hole interconnections in the silicon substrate from the surface.
However, conventional three-dimensional packaging technologies have shortcomings of increased process steps. That is, because processing to make through-hole interconnection in silicon substrate starts from the surface and a via hole is filled with copper, CMP (Chemical Mechanical Polishing) processing from the top surface and re-distribution to connect the copper and a pad after forming the via hole are required. Although copper wiring technology is suitable for fine patterning, increased cost is unavoidable because copper itself is expensive and it is necessary to purchase a specific apparatus additionally.